Molded sheet of thermoplasticized starch / olefin resin composition and manufacturing method thereof

Abstract

To provide a molded sheet of an olefinic resin composition containing heat-plasticized starch, which resists coloring during sheet molding and has improved moldability and durability, and a method for producing the same.SOLUTION: An olefinic resin composition containing heat-plasticized starch and having a melt flow rate (MFR) value of 0.7-1.5 g / 10 min is molded into a sheet, thereby providing a molded sheet.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a molded sheet of a thermoplasticized starch / olefin-based resin composition and a method for producing the same. More specifically, the present invention relates to a molded sheet of a thermoplasticized starch / olefin-based resin composition, which has no decrease in mechanical strength, is excellent in secondary processability such as vacuum forming, and is suppressed in coloration, and a method for producing the same. [Background technology]

[0002] From the viewpoint of reducing carbon dioxide emissions that contribute to global warming, the possibility of using renewable plant-derived components such as cellulose and starch has been studied in various technical fields. In the field of resin molding technology, plant-derived components have long been blended as fillers into general-purpose thermoplastic resins such as polyolefins. However, simply mixing plant-derived components reduces the mechanical strength of the thermoplastic resin, such as its impact strength, and there are problems in that the resin may become discolored or deteriorate due to heat during processing.

[0003] As one of the methods for improving the impact strength of thermoplastic resins, a method using a polymer alloy using thermoplasticized starch (TPS) has been proposed in recent years. As a means for improving the mechanical properties of thermoplastic resins using TPS, Patent Document 1 discloses a resin composition consisting of starch, a polyolefin resin, a polyhydric alcohol that is liquid at room temperature, a surfactant, and a compatibilizer. It is described that the composition is processed by a known processing method to obtain a thermoplastic resin composition molded article having good mechanical properties.

[0004] Patent Document 2 also describes that an olefin resin composition containing thermoplasticized starch is processed into a sheet by a calendar molding method. The calendar molding method is a sheet molding method with a higher yield than the T-die molding method, and is widely used for the production of soft polyvinyl chloride resin sheets, etc. However, since the T-die molding method is a common molding method for olefin resin compositions, there has been a demand for a thermoplasticized starch-containing olefin resin composition that can be processed into a film by the T-die molding method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-210824 A [Patent Document 2] JP 2019-210375 A Summary of the Invention [Problem to be solved by the invention]

[0006] Under such circumstances, the problem to be solved by the present invention is to provide a molded sheet of an olefin resin composition containing thermoplasticized starch, which is suppressed in discoloration during sheet molding using a T-die molding method and has improved moldability and durability, and a method for producing the same.

[0007] In view of the above circumstances, the present inventors have conducted extensive research and found that when an olefin-based resin composition containing thermoplasticized starch has a melt flow rate (hereinafter referred to as "melt flow rate" or "MFR") within a specific range, it becomes possible to process the composition using a T-die molding method, thereby completing the present invention. [Means for solving the problem]

[0008] That is, the present invention relates to a molded sheet obtained by molding an olefin resin composition containing thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 g / 10 min into a sheet shape. The present invention further relates to a molded sheet obtained by extrusion molding an olefin-based resin composition obtained by melt-kneading an olefin-based resin mixture containing starch, a polyhydric alcohol, and an olefin-based resin, wherein the melt flow rate (MFR) of the olefin-based resin composition is 0.7 to 1.5 g / 10 min. The present invention further relates to a molded article obtained by thermoforming the above molded sheet. The present invention further relates to a method for producing a molded sheet, comprising the steps of melt-kneading an olefin-based resin mixture containing starch, a polyhydric alcohol and an olefin-based resin to form an olefin-based resin composition containing thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 g / 10 min, and extruding the olefin-based resin composition to form it into a sheet shape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] One embodiment of the present invention is a molded sheet obtained by molding an olefin-based resin composition containing thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 g / 10 min into a sheet shape. The olefin-based resin composition used in the molded sheet of the embodiment is a mixture of thermoplasticized starch (hereinafter, sometimes referred to as "TPS") and an olefin-based resin. Starch is composed of amorphous amylose, a long-chain molecule with a molecular weight of tens of thousands, and amylopectin, which has a semi-crystalline structure with many branches and a molecular weight of hundreds of thousands and has a granular structure. Starch does not exhibit thermoplasticity until the temperature reaches a thermal denaturation. Thermoplasticized starch (TPS) is a material that breaks down this granular structure by heating and kneading starch together with a plasticizer, thereby increasing uniformity and decreasing crystallinity, and enabling thermoplastic processing like general-purpose thermoplastic resins. A detailed manufacturing method of TPS is described, for example, in the above-mentioned Patent Document 1.

[0010] In the olefin resin composition used in one embodiment of the present invention, the content of TPS is 20 to 70% by weight, preferably 25 to 65% by weight, and more preferably 30 to 60% by weight. If this ratio is 70% by weight or more, the mechanical properties of the molded product of the olefin resin composition may be insufficient. As described above, TPS is a hydrophilic polymer composition containing a water-soluble plasticizer, and is poor in water resistance. This drawback can be overcome by blending with a highly hydrophobic polyolefin resin, but if the TPS is blended in the olefin resin composition at a high blending ratio of 70% by weight or more, problems may occur in the water resistance of the composition. On the other hand, if the blending ratio of TPS in the olefin resin composition is 20% by weight or less, the T-die moldability becomes insufficient. Not only does this cause problems in the moldability in T-die molding, but it is also undesirable from the viewpoint of using plant-derived components. In T-die molding, various properties are required of the olefin resin composition, such as flowability in a molten state, swell, slipperiness in a solid state, and peelability. As in the embodiment, TPS can be blended with a polyolefin resin and T-die molding can be performed without problems. The reason for this is not clear, but it is speculated that the flow characteristics suitable for T-die molding are obtained by blending a highly hydrophobic polyolefin resin melt with a highly polar TPS melt, which has high cohesive strength.

[0011] The melt flow rate (MFR) of the olefin resin composition used in the embodiment is preferably 0.7 to 1.5 g / 10 min. If the MFR of the olefin resin composition is greater than 1.5 g / 10 min, it may be difficult to form a film by extrusion molding. If the MFR of the olefin resin composition is less than 0.7 g / 10 min, the temperature of the resin composition may rise during extrusion molding, and the thermoplasticized starch may return to starch. The MFR is a value measured at 190°C and a load of 2.16 kg according to JIS K7210-1.

[0012] The olefin-based resin composition used in the embodiment includes a propylene-based resin and an ethylene-based resin. Examples of the propylene-based resin include a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-α-olefin random copolymer, and a propylene block copolymer obtained by homopolymerizing propylene and then copolymerizing ethylene and propylene. Examples of the ethylene-based resin include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, very low-density polyethylene, and an α-olefin resin mainly composed of an α-olefin having 4 or more carbon atoms. The olefin-based resin composition used in the embodiment can be obtained by appropriately mixing the propylene-based resin and the ethylene-based resin. The propylene-based resin and the ethylene-based resin will be described in detail later.

[0013] In addition, the olefin resin composition used in the embodiment may contain an organic lubricant as necessary. As the organic lubricant, the following can be suitably used: hydrocarbon lubricant: paraffin wax, synthetic polyethylene, liquid paraffin, etc.; higher alcohol fatty acid: stearic acid, venic acid, 12-hydroxystearic acid, stearyl alcohol, etc.; amide fatty acid: stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, etc.; metal soap: calcium stearate, zinc stearate, magnesium stearate, etc.; ester lubricant: glycerin monostearate, glycerin monooleate, butyl stearate, etc. The organic lubricant reduces friction between the olefin resin composition and the processing machine, improves the fluidity and peelability of the olefin resin composition, and plays a role in improving the molding efficiency and the appearance of the molded product. The organic lubricant is preferably contained in an amount of 0.3 to 3% by weight relative to the olefin resin composition.

[0014] An example of a commercially available olefin resin composition used in the embodiment is NEOPLA S-SERIES manufactured by Shiraishi Biomass Co., Ltd., and the like. The manufacturing method thereof is described in Patent Document 1.

[0015] In the present embodiment, the molded sheet generally refers to a thin and wide shape, and includes a film, a foil, a membrane, and the like.

[0016] Another embodiment of the present invention is a molded sheet obtained by extrusion molding an olefin resin composition obtained by melt-kneading an olefin resin mixture containing starch, a polyhydric alcohol, and an olefin resin, wherein the olefin resin composition has a melt flow rate (MFR) of 0.7 to 1.5 g / 10 min.

[0017] As the starch used in the embodiment, any starch that is commercially available can be used. The starch may be either starch of natural origin or processed starch. Examples of starches of natural origin include corn starch, wheat starch, potato starch, sweet potato starch, and tapioca starch, and it is preferable to use corn starch because it is widely distributed and has stable quality. In addition, examples of processed starches include acetylated starch, phosphorylated starch, oxidized starch, and hydroxypropyl starch, and among these, it is preferable to use phosphorylated starch with a phosphorus content of 0.5% or less.

[0018] When producing the TPS used in the embodiment, a polyhydric alcohol can be used as a plasticizer for starch. Preferably, a polyhydric alcohol that has a large plasticizing effect on starch and is liquid at room temperature (preferably has a melting point lower than 25°C and a boiling point higher than 25°C) can be used. Examples of polyhydric alcohols that are liquid at room temperature for producing the TPS used in the embodiment include glycerin, diglycerin, polyglycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 200, molecular weight 300, molecular weight 400, molecular weight 600), 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. Glycerin is particularly preferred. One type of polyhydric alcohol can be used from among these, and multiple types of polyhydric alcohols can be mixed and used. In addition, a polyhydric alcohol that is liquid at room temperature and a polyhydric alcohol that is solid at room temperature can be used in combination, as necessary. Examples of polyhydric alcohols that are solid at room temperature include glucose, fructose, sorbitol, sucrose, trehalose, and maltose, with sorbitol being particularly preferred.

[0019] In an embodiment, the blending ratio of starch and polyhydric alcohol is preferably 10 / 90 to 40 / 60 in terms of the weight ratio of these components (starch / polyhydric alcohol). If the blending ratio of polyhydric alcohol is less than 10% by weight, the collapse of crystal granules during TPS production may be insufficient, and the plasticization of the resulting TPS may also be insufficient. On the other hand, if the blending ratio of polyhydric alcohol is more than 40% by weight, the strength of a molded product of an olefin resin composition containing TPS may decrease, and the surface may become sticky.

[0020] The olefin resin used in the embodiment is a resin made of a homopolymer of one type of olefin or a copolymer of two or more types of olefin. The olefin resin does not include a resin modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative. Examples of the olefin resin include a propylene resin and an ethylene resin. These polyolefin resins may be used alone or in combination of two or more. Preferably, a mixture of a propylene resin and an ethylene resin is used.

[0021] Examples of the propylene-based resin used in the embodiment include a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-α-olefin random copolymer, and a propylene block copolymer obtained by homopolymerizing propylene and then copolymerizing ethylene and propylene.

[0022] The melting point (Tm) of the propylene-based resin used in the embodiment is preferably 90 to 160°C, more preferably 100 to 155°C, and more preferably 105 to 155°C, from the viewpoint of improving the appearance of the molded article and increasing mechanical strength such as rigidity and impact strength. The melting point (Tm) is the peak temperature at which the amount of endotherm is maximum in the melting endotherm curve measured according to the above-mentioned method.

[0023] The propylene-based resin used in the embodiment can be produced by a solution polymerization method, a slurry polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like. These polymerization methods may be used alone or in combination of two or more. Examples of the method for producing the propylene-based resin include the polymerization methods described in "New Polymer Manufacturing Process" (edited by Saeki Koji, published by Kogyo Chosakai (1994)), JP-A-4-323207, and JP-A-61-287917.

[0024] The propylene-based resin used in the embodiment may be a commercially available resin. Examples of commercially available propylene-based resins include Novatec PP, Wintech, Wellnex, and Waymax manufactured by Japan Polypropylene Corporation, Prime Polypro manufactured by Prime Polymer Co., Ltd., and Noblen and Excellen manufactured by Sumitomo Chemical Co., Ltd.

[0025] Examples of the ethylene-based resin used in the embodiment include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, very low-density polyethylene, and α-olefin resins mainly composed of α-olefins having 4 or more carbon atoms. The melting point (Tm) of the ethylene-based resin used in the embodiment is preferably 60 to 160°C, more preferably 70 to 150°C, and even more preferably 80 to 140°C, from the viewpoint of improving the appearance of the molded article and increasing mechanical strength such as rigidity and impact strength. The melting point (Tm) is the peak temperature of the peak at which the amount of endotherm is maximum in the melting endotherm curve measured according to the above-described method.

[0026] The ethylene resin used in the embodiment can be produced by the same method as the above-mentioned propylene resin production method. The ethylene resin used in the embodiment can be a commercially available resin. Examples of commercially available ethylene resins include Novatec, Harmolex, and Kernel manufactured by Japan Polyethylene Co., Ltd., Evolue, Evolue H, Hi-Zex, and Ult-Zex manufactured by Prime Polymer Co., Ltd., and Excellen and Sumikathene manufactured by Sumitomo Chemical Co., Ltd.

[0027] The olefin resin used in the embodiment can be used by appropriately adjusting the compounding ratio of the propylene resin and the ethylene resin depending on the properties required for the secondary molded product.

[0028] In an embodiment, the starch, polyhydric alcohol, and olefin resin are mixed to obtain an olefin resin mixture. The olefin resin mixture is melted and kneaded to react the starch with the polyhydric alcohol to thermoplasticize (to convert the starch into TPS), and an olefin resin composition can be obtained. Here, the olefin resin mixture may contain an organic lubricant. As the organic lubricant, the following can be suitably used: hydrocarbon lubricant: paraffin wax, synthetic polyethylene, liquid paraffin, etc.; higher alcohol fatty acid: stearic acid, venic acid, 12-hydroxystearic acid, stearyl alcohol, etc.; amide fatty acid: stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, etc.; metal soap: calcium stearate, zinc stearate, magnesium stearate, etc.; ester lubricant: glycerin monostearate, glycerin monooleate, butyl stearate, etc. The organic lubricant may be contained in an amount of 0.3 to 3% by weight relative to the olefin resin mixture. In addition, the olefin resin mixture may contain a polymerization initiator such as an organic peroxide. As the organic peroxide as the polymerization initiator, peroxyketals: 1,1-di(t-hexylperoxy)cyclohexene, 1,1-di(t-butylperoxy)cyclohexene, etc., dialkyl peroxides: dicumyl peroxide, α,α'-di(t-butyloxy)diisopropylbenzene, etc., peroxyesters: t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, etc., dialkyl peroxides: dibenzoyl peroxide, dilauroyl peroxide, etc. can be suitably used. The organic peroxide may be contained in an amount of 0.01 to 1.0% by weight relative to the olefin resin mixture.

[0029] A surfactant may be added to the olefin resin mixture in order to improve melt-kneadability by reducing the interfacial tension between the olefin resin and the TPS produced from starch. As the surfactant in the embodiment, any of anionic, cationic, amphoteric, and nonionic surfactants may be used. From the viewpoint of improving the heat resistance of the olefin resin composition obtained from the olefin resin mixture, it is preferable to use an anionic, amphoteric, or nonionic surfactant. In addition, a mixture of multiple types of surfactants may be used. From the viewpoint of improving the compatibility between the olefin resin and the TPS, it is particularly preferable to use a nonionic surfactant having an HLB value of 3 to 9.

[0030] The amount of the surfactant to be added is 0.5 to 7% by weight, preferably 1.0 to 5% by weight, based on the olefin resin used in the embodiment. If the amount is less than 0.5% by weight, it is difficult to obtain the effect of improving the mechanical properties due to improved compatibility, and if the amount is 7% by weight or more, the strength of the molded product obtained from the olefin resin composition produced may decrease, or the surface may become sticky.

[0031] In addition, the olefin resin mixture may contain known substances generally added to olefin resins depending on the purpose, such as stabilizers such as antioxidants, heat stabilizers, neutralizing agents, and ultraviolet absorbers, bubble inhibitors, flame retardants, flame retardant assistants, dispersants, antistatic agents, lubricants, antiblocking agents such as silica, colorants such as dyes and pigments, plasticizers, nucleating agents, and crystallization accelerators. These substances can be added to the olefin resin mixture and melt-kneaded to obtain an olefin resin composition containing these substances.

[0032] The olefin resin mixture may further contain glass flakes, mica, glass powder, glass beads, talc, clay, alumina, carbon black, wolsenite, and other plate-like or powder-like inorganic compounds, whiskers, etc. These substances may be added to the olefin resin mixture and melt-kneaded to obtain an olefin resin composition containing these substances.

[0033] If necessary, the olefin resin mixture may contain one or more elastomers, such as ethylene-α-olefin random copolymers, ethylene-α-olefin-non-conjugated polyene random copolymers, hydrogenated block copolymers, other elastic polymers, and mixtures thereof.

[0034] The melt flow rate (MFR) value of the olefin resin composition obtained here is preferably 0.7 to 1.5 g / 10 min. If the MFR of the olefin resin composition is greater than 1.5 g / 10 min, film formation processing by extrusion molding (particularly the T-die molding method described later) may be difficult. If the MFR of the olefin resin composition is less than 0.7 g / 10 min, the temperature of the resin composition may rise during T-die molding processing, and the thermoplasticized starch may return to starch. The MFR is a value measured at 190°C and a load of 2.16 kg according to JIS K7210-1. Two or more of the obtained olefin resin compositions may be mixed to adjust the MFR to 0.7 to 1.5 g / 10 min.

[0035] The obtained olefin resin composition can be extruded to obtain a molded sheet of the embodiment. The extrusion molding can be performed by extruding the olefin resin composition from dies of various shapes. In particular, it is preferable to perform the extrusion molding by a T-die molding method in which the composition is extruded from a T-die. The T-die molding method will be described later. The molded sheet of the embodiment obtained by T-die molding can also be further stretched to obtain a stretched film.

[0036] The width of the molded sheet in the embodiment is preferably 200 to 2000 mm, more preferably 300 to 1500 mm, and particularly preferably 500 to 1300 mm, from the viewpoints of efficiency in sheet production and ease of secondary processing.

[0037] The thickness of the molded sheet in the embodiment is preferably 0.1 to 2.0 mm, more preferably 0.2 to 1.2 mm, and particularly preferably 0.4 to 1.0 mm, from the viewpoints of efficiency in sheet production and ease of secondary processing.

[0038] Further, another embodiment of the present invention is a molded product obtained by thermoforming the molded sheet of the embodiment. Thermoforming refers to molding a molded sheet made of a softened olefin resin composition using a mold. Thermoforming can be performed by a general method such as vacuum molding or compressed air pressure molding. Examples of molded products of the embodiment include agricultural and horticultural products such as food trays, cups, containers, blister packs, various covers, pipes, electronic parts, vehicle parts, trays for automobile parts, trays for electronic parts, seedling pots, seedling trays, food packaging materials, medical packaging materials, and cosmetic packaging materials.

[0039] Another embodiment of the present invention is a method for producing a molded sheet, which includes a step of melt-kneading an olefin resin mixture containing starch, a polyhydric alcohol, and an olefin resin to form an olefin resin composition containing thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 g / 10 min, and extruding the olefin resin composition to form a sheet. In the production method of the embodiment, first, starch, a polyhydric alcohol, an olefin resin, and optionally an organic lubricant, an organic peroxide, a surfactant, and other additives are mixed to obtain an olefin resin mixture. This olefin resin mixture is fed into a Banbury mixer, a kneader, a Henschel mixer, or a single- or multi-screw extruder, and melt-kneaded at preferably 80°C to 230°C, more preferably 100°C to 200°C. This step allows the plasticizer to penetrate into the inside of the starch granules and destroy their regular structure, forming a homogeneous, thermally fluid TPS, and the olefin resin and the TPS are melt-kneaded to form a homogeneous olefin resin composition. The melt flow rate (MFR) value of this olefin resin composition is 0.7 to 1.5 g / 10 min. This olefin resin composition is extruded to form a sheet. Extrusion molding can be performed by extruding the olefin resin composition from dies of various shapes. In particular, it is preferable to perform extrusion from a T-die by a T-die molding method. The T-die molding method is a method in which a molten olefin resin composition is extruded from a slit to form a thin film. The olefin resin composition of the embodiment can be molded into a molded sheet without the inconvenience of TPS returning to starch, since the temperature of the resin composition does not rise too much when molding by the T-die molding method. EXAMPLES

[0040] The present invention will be described below with reference to examples and comparative examples. The methods for producing evaluation samples used in the examples and comparative examples are described below.

[0041] (1) TPS-blended olefin resin composition for evaluation The olefin resin compositions used were from the NEOPLA-S series manufactured by Shiraishi Biomass Co., Ltd. The resin compositions used were four types, NEOPLA-S-212, 211, 157, and 214, and their MFRs were as follows: S-212: 1.0g / 10min S-211: 0.5g / 10min S-157: 0.3g / 10min S-214: 2.6g / 10min

[0042] These resin compositions were used and blended as shown in Table 1 to prepare olefin-based resin compositions.

[0043] [Table 1]

[0044] (2) Example 1: T-die molding method for evaluation samples Using a Hitachi Zosen T-die extrusion molding machine, a sheet sample for evaluation was prepared under the following conditions: Screw diameter: 120mm Screw type: Full flight Molding conditions Air knife method Cylinder temperature setting: 170℃ First roll temperature setting: 45℃ Second roll temperature setting: 30℃ Take-off speed: 10m / min Sheet width: 800mm Sheet thickness: 0.5mm

[0045] Each molded sheet was evaluated as follows. (Evaluation 1) T-die film forming properties When the above T-die molding method was performed, the resin composition flowed smoothly and a homogeneous molded sheet was obtained, which was evaluated as "good." On the other hand, when the resin composition foamed or the molded sheet had a lot of so-called eye discharge, which was performed, it was evaluated as "poor." When a film could not be appropriately formed by the T-die molding method, it was evaluated as "film formation impossible."

[0046] (Evaluation 2) DuPont impact test The impact strength of the molded sheet was measured according to JIS K 5600-5-3 (weight drop resistance test for coating film). Measuring equipment used: DuPont impact tester manufactured by Toyo Tester Kogyo Co., Ltd. Striker used: Tip R6.35mm, φ12.7mm Receiving base: φ44mm Measurement temperature: 23℃

[0047] (Evaluation 3) Secondary processability of molded sheet Sheets were molded under the following conditions and evaluated. Sheets that showed no unevenness in thickness, twisting, or tearing were rated as "good," and sheets that showed unevenness in thickness, twisting, or tearing were rated as "poor." Molding conditions: The sheet was preheated at 250°C for 30 seconds and then shaped by vacuum molding. Tray shape: 310mm x 410mm, with 4 recesses of 287mm x 91mm and 50mm depth

[0048] Molded sheets were produced by the T-die molding method using resin compositions having various melt flow rates. When a resin composition with an inappropriate melt flow rate was used, there was a problem that the film-forming property was difficult (Comparative Example 2) or the secondary processability of the molded sheet was difficult (Comparative Example 1). In contrast, a resin composition having an appropriate melt flow rate was excellent in film-forming property, and the strength and secondary processability of the obtained molded sheet were also high (Example 1, Example 2). It can be seen that it is important to use a resin composition with an appropriate melt flow rate in producing a molded sheet.

Claims

1. The molded sheet has a width of 300 to 1500 mm and a thickness of 0.2 to 1.2 mm and is obtained by T-die extrusion molding an olefin resin composition containing thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 g / 10 min measured at 190°C under a load of 2.16 kg.

2. 2. The molded sheet of claim 1, wherein the olefin-based resin composition comprises a propylene-based resin and an ethylene-based resin.

3. 3. The molded sheet according to claim 1, wherein the olefin resin composition further comprises an organic lubricant, and the organic lubricant is contained in an amount of 0.3 to 3% by weight based on the olefin resin composition.

4. A molded sheet having a width of 300 to 1500 mm and a thickness of 0.2 to 1.2 mm, which is obtained by extruding an olefin-based resin composition obtained by melt-kneading an olefin-based resin mixture containing starch, a polyhydric alcohol, and an olefin-based resin through a T-die, The molded sheet as described above, wherein the melt flow rate (MFR) of the olefin resin composition measured at 190° C. under a load of 2.16 kg is 0.7 to 1.5 g / 10 min.

5. 5. The molded sheet of claim 4, wherein the olefin-based resin mixture comprises a propylene-based resin and an ethylene-based resin.

6. 6. The molded sheet according to claim 4, wherein the olefin-based resin mixture further contains an organic lubricant, and the organic lubricant is contained in an amount of 0.3 to 3% by weight based on the olefin-based resin mixture.

7. The molded sheet according to any one of claims 4 to 6, wherein the olefin-based resin mixture further contains an organic peroxide.

8. A molded product obtained by thermoforming the molded sheet according to any one of claims 1 to 7.

9. melt-kneading an olefin-based resin mixture containing starch, a polyhydric alcohol and an olefin-based resin to form an olefin-based resin composition containing a thermoplasticized starch and having a melt flow rate (MFR) value of 0.7 to 1.5 grams / 10 minutes measured at 190° C. under a load of 2.16 kg; The olefin resin composition is extruded through a T-die and formed into a sheet shape. A method for producing a molded sheet, comprising the steps of:

10. The method for producing a molded sheet according to claim 9, wherein the olefin-based resin mixture further contains an organic lubricant and / or an organic peroxide.

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